Hamburg sporting director Frank Arnesen has appointed himself coach of the Bundesliga strugglers on a temporary basis until a permanent replacement for the sacked Michael Oenning is found.
"I will remain in charge until a new coach is appointed, which may not be until the winter break," said Dane Arnesen, 55.
Arnesen will be assisted by Rodolfo Cardoso, who had been working as caretaker coach and oversaw a 2-1 win at Stuttgart and a 2-1 home defeat to Schalke.
Hamburg failed in a bid to bring back Huub Stevens for a second spell in charge, with the Dutchman joining Schalke instead.
The side that currently props up the Bundesliga then saw Basel coach Thorsten Fink reject their advances.
"I acknowledge the interest from Hamburg but for the moment I want to concentrate on my job at Basel," Fink was quoted as saying in the German daily Die Welt.
Another man linked to the job in the German media is the Dutchman Guus Huddink, currently the coach of the Turkish national side.